The central theme of this proposal is the redox-modulated protein interactions at the surface/solution interface. One subproject is concerned with the electrochemical studies of p53 (a tumor suppression protein) and the correlation of the externally applied potential to the extent of p53/DNA binding. The other subproject will deal with the redox reactions inherent in amyloidogenic proteins and their relationships with the protein fibrillation/aggregation processes. The proposed work will utilize a variety of analytical and surface techniques to study DNA/protein and protein/small molecule interactions. These techniques include, but are not limited to, voltammetry, flow injection quartz crystal microbalance, surface plasmon resonance, scanning tunneling microscopy, scanning electrochemical microscopy, and atomic force microscopy. Particular emphasis will be placed on the voltammetric and surface characterization of p53 protein and alpha-synuclein and beta-amyloid. Various immobilization schemes will be explored to immobilize proteins with optimal surface configuration (i.e., surface coverage and molecular orientation) and without significant conformational changes. Kinetic measurements will also be performed on the interaction of these species with their biological partners (e.g., binding of p53 to its consensus DNA under various applied potentials and interaction of potential therapeutic drugs with amyloidogenic proteins). The influence of various species (e.g., redox-active metal ions and organic molecules and electroactive metalloproteins) on the voltammetric behavior and binding kinetics of p53 and amyloidogenic proteins will also be investigated. The redox properties of these proteins will be correlated with findings from kinetic studies and surface characterization. Attempts will also be made in the identification of intermediates of amyloidogenic protein fibrillation and aggregation. The studies proposed herein should help elucidate the mechanisms involved in the interactions of the two important types of proteins with other species under physiologically relevant conditions and provide useful information to the effective development of therapeutic drugs for cancer and neurodegenerative diseases.